(1) Field of the Invention
The present invention relates to a technique suitably used for, for example, processing forms in banking facilities; and more particularly, to a technique for recognizing characters written in color forms.
(2) Description of Related Art
In banking facilities and so on, as an apparatus for reading character information written in forms as image data and then recognizing the data as characters, image reading apparatus such as optical character recognition apparatus (OCR) is used. By employing OCR apparatus, the efficiency of the transaction of business has been improved.
In conventional OCR technique, image data on a form is obtained as a monochrome binary image, and then, recognized as characters. For example, with respect to a form, on which ruled-lines, guide characters and the like are printed with predetermined dropout colors such as green color, red color and the like, characters, which are written with colors (black color etc.) other than the dropout colors in character recognition target areas (spaces for filling with characters), are read out as monochrome binary image by an OCR apparatus; and based on the binary image, character recognition processing is carried out (refer to the following patent documents 1-3).
[Patent document 1] Japanese Patent Laid-Open No. 2000-322510
[Patent document 2] Japanese Patent Laid-Open No. 2001-297303
[Patent document 3] Japanese Patent Laid-Open No. 2003-196592
In order to increase the legibility of information written on forms and to highlight characters written thereon, color forms, on which ruled-lines, background, guide characters and the like are printed using various colors, are occasionally used.
In the conventional OCR technique, image data on a form is obtained as a monochrome binary image, and based on the binary image, characters are recognized. Accordingly, in color forms, which ruled-lines, background, guide characters and the like are printed thereon with colors other than dropout colors as described above, there reside such problems that, when ruled-lines, background, guide characters and the like are positioned adjacent to written characters, or when the written characters come into contact or cross with these ruled-lines, background or guide characters, recognition of the written characters is interfered resulting in a reduced character recognition ratio. Further, in the case where background color or solid coloring such as half-tone dot meshing is made on the character recognition target area, the character recognition is interfered resulting in a reduced character recognition ratio.
That is, in the conventional OCR technique, characters written in a solid colored area using a color other than dropout color, or likewise, characters, which are positioned adjacent to or come into contact with ruled-lines, background, guide characters or the like using a color other than dropout colors, are hardly recognized with high accuracy.
Further, with respect to color forms, which have spaces for filling with characters and having solid coloring and guide characters with various colors, and are originally not given with consideration about the character recognition by the OCR apparatus, if the character information written in the spaces for filling with characters can be read using an OCR apparatus, a high convenience can be expected.